scholarly journals Suppression of Sclerotinia Stem Rot of Soybean by Lactofen Herbicide Treatment

1999 ◽  
Vol 89 (7) ◽  
pp. 598-602 ◽  
Author(s):  
E. K. Dann ◽  
B. W. Diers ◽  
R. Hammerschmidt
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Lesion Size ◽  
Stem Rot ◽  
Growth Stages ◽  
Sclerotinia Stem Rot ◽  
High Disease Severity ◽  
Disease Pressure ◽  
Seed Yields ◽  
Field Plots

Severity of Sclerotinia stem rot of soybean after treatment with lactofen (Cobra) and other herbicides was assessed in field experiments conducted in Michigan from 1995 to 1997. At sites where disease pressure was high, disease severity was reduced 40 to 60% compared with controls when lactofen was applied at the V3 (1995 and 1996) or R1 (1997) growth stages. Corresponding seed yields were unchanged or up to 20% greater when lactofen was applied at the R1 stage in 1997. Disease severity was not reduced by lactofen treatments in years and at sites where disease pressure was low to medium, and corresponding yields often were reduced by ≈10%. High levels of glyceollin accumulated in lactofen-injured leaves collected from field plots in 1996 and 1997. High glyceollin content in lactofen-treated leaves was associated with significant reductions in lesion size when leaves were challenge-inoculated with Sclerotinia sclerotiorum.

scholarly journals Soybean Stem Lignin Concentration Relates to Resistance to Sclerotinia sclerotiorum

Plant Disease ◽  
2009 ◽  
Vol 93 (2) ◽  
pp. 149-154 ◽  
Author(s):  
A. J. Peltier ◽  
R. D. Hatfield ◽  
C. R. Grau
Keyword(s):  
Disease Resistance ◽  
Sclerotinia Sclerotiorum ◽  
Field Experiments ◽  
Lignin Content ◽  
Stem Rot ◽  
Growth Stages ◽  
Soybean Plant ◽  
Sclerotinia Stem Rot ◽  
Lignin Concentration ◽  
Stem Lignin

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is an economically important disease of soybean (Glycine max) in the north-central United States and other temperate regions throughout the world. The occurrence and severity of Sclerotinia stem rot in the field is highly dependent upon prevailing environmental conditions, which can prove problematic when evaluating soybean accessions for resistance. The identification of an environmentally stable plant trait associated with resistance to S. sclerotiorum could be used to indirectly screen for resistance and would prove useful in the identification and development of resistant germplasm. Observations of the soybean–S. sclerotiorum interaction suggest a role for preformed stem lignin content in disease resistance. Although S. sclerotiorum produces numerous enzymes that degrade plant cell wall components, no lignin-degrading enzymes have been reported. Despite a hypothesized direct relationship between preformed lignin content and disease resistance, previous studies on soybean have correlated lignin content to nutritional value and not to disease resistance. We hypothesized that plants with low stem lignin are more susceptible and exhibit greater Sclerotinia stem rot severity than plants with high lignin concentrations. Six soybean accessions that varied in response to S. sclerotiorum were selected for study in a series of field experiments. Soybean stems were sampled at reproductive developmental stages that correspond to specific events in both soybean plant development and the Sclerotinia stem rot disease cycle. The lignin concentration of stem component samples was quantified. Soybean accessions expressed statistically different disease phenotypes in both 2004 and 2006. Lignin concentrations differed among accessions, growth stages, and plant parts. Results were contrary to our hypothesis, with positively ranked correlations observed between accession Sclerotinia stem rot severity and lignin concentration for all nodes and internodes assayed. For the R3 growth stage, lignin concentration of the internode between the fourth and fifth trifoliate leaves correlated best with disease severity data from each year (P = 0.005). These results indicate that resistance is related to low stem lignin concentration and that soybean stem lignin concentration can be used as a biological marker to select for resistance to S. sclerotiorum.

scholarly journals Silicon Alleviates the Disease Severity of Sclerotinia Stem Rot in Rapeseed

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuxia Feng ◽  
Yuxin Hu ◽  
Pengpeng Fang ◽  
Xiangjun Zuo ◽  
Jinxiong Wang ◽  
...  
Keyword(s):  
Disease Severity ◽  
Seed Quality ◽  
Agronomic Traits ◽  
Induced Defense ◽  
Disease Incidence ◽  
Defense Responses ◽  
Lesion Size ◽  
Stem Rot ◽  
Lesion Length ◽  
Sclerotinia Stem Rot

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a devastating disease in rapeseed. The objective of this study was to investigate the role and the mechanism of silicon (Si) in alleviating the disease severity of S. sclerotiorum in rapeseed. In the absorption assays, the rapeseed that absorbed 10 mM of K2SiO3 exhibited an 86% decrease in lesion size on infected leaves as compared with controls. In the spray assay, the lesion length on rapeseed stems was reduced by 30.5–32.9% with the use of 100 mM of a foliar Si fertilizer as compared with controls. In the pot assay, the lesion length on rapeseed stems was reduced by 34.9–38.3% when using the Si fertilizer as basal fertilizer. In the field assay, both the disease incidence and disease index of sclerotinia stem rot were significantly reduced with the usage of a solid Si fertilizer, Si foliar fertilizer, and the application of both, without negative affection on the main agronomic traits and seed quality of rapeseed. The transcriptome sequencing, quantitative reverse transcription PCR (qRT-PCR), and biochemical assays between K2SO4- and K2SiO3- treated rapeseed leaves revealed that Si promoted the biosynthesis of defense-related substances and enhanced the antioxidation and detoxification abilities of rapeseed after infection. Thus, this study concluded that Si can alleviate the disease severity of S. sclerotiorum in rapeseeds, partially due to the induced defense responses.

Effect of Sclerotinia Stem Rot on Yield of Soybean Inoculated at Different Growth Stages

Plant Disease ◽  
2004 ◽  
Vol 88 (3) ◽  
pp. 297-300 ◽  
Author(s):  
G. A. Danielson ◽  
B. D. Nelson ◽  
T. C. Helms
Keyword(s):  
Seed Weight ◽  
Oil Content ◽  
Field Experiments ◽  
Seed Protein ◽  
Disease Incidence ◽  
Stem Rot ◽  
Growth Stages ◽  
Diseased Plant ◽  
Sclerotinia Stem Rot ◽  
Effect On Yield

The effects of Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, on yield of soybean were evaluated in the field with two cultivars in maturity group 0. Plants were inoculated at two growth stages, R3 and R5, using two inoculation methods. Seed weight, seed and pod numbers, seed protein, and oil content were measured. The effects of disease on yield were variable. Disease resulted in significant seed weight loss, with reductions per diseased plant ranging from 18.8 to 38.6%. The estimated yield loss per 10% disease incidence ranged from 83.2 to 229.0 kg/ha, with an average loss of 136.6 kg/ha for four field experiments. A reduction in the number of seeds and pods per plant and seed oil content occurred in some, but not all, experiments. Seed protein was not affected. When disease reduced seed weight, seed and pod numbers, or oil content, there was no growth stage × treatment interaction in the experiments, indicating that inoculation at R5 compared with R3 had a similar effect on yield.

scholarly journals Case Study of an Epidemiological Approach Dissecting Historical Soybean Sclerotinia Stem Rot Observations and Identifying Environmental Predictors of Epidemics and Yield Loss

2018 ◽  
Vol 108 (4) ◽  
pp. 469-478 ◽  
Author(s):  
Mamadou L. Fall ◽  
John F. Boyse ◽  
Dechun Wang ◽  
Jaime F. Willbur ◽  
Damon L. Smith ◽  
...  
Keyword(s):  
Disease Severity ◽  
Yield Loss ◽  
Historical Data ◽  
Severity Index ◽  
Stem Rot ◽  
Total Precipitation ◽  
Disease Severity Index ◽  
Sclerotinia Stem Rot ◽  
Environmental Predictors ◽  
Epidemiological Approach

Sclerotinia sclerotiorum is a significant threat to soybean production worldwide. In this study, an epidemiological approach was used to examine 11 years of historical data from a soybean management performance trial in order to advance our understanding of Sclerotinia stem rot (SSR) development and to identify environmental predictors of SSR epidemics and associated yield losses. Recursive partitioning analysis suggested that average air temperature and total precipitation in July were the most significant variables associated with disease severity. High levels of SSR disease severity index were observed when the average temperature in July was below 19.5°C and total precipitation in July was moderate, between 20 and 108.5 mm. A biphasic sigmoidal curve accurately described the relationship between SSR disease severity index (DSI) and yield, with a DSI threshold of 22, below which minimal yield loss was observed. A 10% increase in the DSI, from 22.0 to 24.2, led to an 11% decrease in yield, from 3,308.14 to 2,951.29 kg/ha. Also, a yield threshold (3,353 kg/ha) that was higher than the annual U.S. average soybean yield (3,039.7 kg/ha) was suggested as an expected yield under low or no SSR pressure in the U.S. Midwest. These thresholds can allow soybean stakeholders to assess the value of disease control and establish an SSR baseline for cost-effective management to protect yields. Because S. sclerotiorum has more than 400 plant host species, and because having quantitative information concerning crop losses is crucial for decision making, this study shows the usefulness of historical data on SSR and, hence, can serve as a model in other SSR pathosystems (canola, dry bean, potato, pea, and so on).

Evaluation of disease forecasting variables for sclerotinia stem rot (Sclerotinia sclerotiorum) of canola

2000 ◽  
Vol 80 (4) ◽  
pp. 889-898 ◽  
Author(s):  
M. Bom ◽  
G. J. Boland
Keyword(s):  
Soil Moisture ◽  
Disease Severity ◽  
Sclerotinia Sclerotiorum ◽  
Prediction Models ◽  
Disease Incidence ◽  
Stem Rot ◽  
Disease Prediction ◽  
Strong Correlations ◽  
Sclerotinia Stem Rot ◽  
Spring Canola

Selected environmental, crop and pathogen variables were sampled weekly from winter and spring canola crops before and during flowering and evaluated for the ability to predict sclerotinia stem rot, caused by Sclertinia sclerotirum. Linear and nonlinear relationships were examined among variables but, because no strong correlations were observed between final disease incidence and any of the variables tested, a categorical approach (e.g., disease severity) was used instead. Disease severity in individual crops was categorized as low (< 20% diseased plants) or high (> 20% disease), and differences in weekly rainfall, soil moisture, crop height, percentage of petal infestation, and number of apothecia m−2 and clumps of apothecia m−2 were significantly associated with differences in disease severity within or between years. Two disease prediction models were compared for the ability to predict low or high disease severities using petal infestation alone, or petal infestation in combination with soil moisture. The model that included petal infestation and soil moisture predicted more fields correctly than the model using petal infestation alone, but the accuracy of both was affected by the timing of soil moisture measurements in relation to petal infestation, and threshold values used in discriminating categories of soil moisture and petal infestation. Key words: Brassica rapa, Brassica napus, Sclerotinia sclerotiorum, disease prediction

scholarly journals Assessing the Adequacy of the Simulation Model LATEBLIGHT Under Nicaraguan Conditions

Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 839-846 ◽  
Author(s):  
Jorge Ulises Blandón-Díaz ◽  
Gregory A. Forbes ◽  
Jorge L. Andrade-Piedra ◽  
Jonathan E. Yuen
Keyword(s):  
Late Blight ◽  
Simulation Model ◽  
Disease Severity ◽  
Field Experiments ◽  
Durable Resistance ◽  
Potato Production ◽  
Potato Cultivars ◽  
Disease Progress ◽  
High Disease Severity ◽  
Fungicide Control

In this study, the adequacy of the late blight simulation model LATEBLIGHT (version LB2004) was evaluated under Nicaraguan conditions. During 2007 to 2008, five field experiments were conducted in three potato-production regions in northern Nicaragua. Two susceptible (‘Cal White’ and ‘Granola’) and one resistant (‘Jacqueline Lee’) potato cultivars were evaluated without use of fungicides and with three application intervals (4, 7, and 14 days) of the fungicide chlorothalonil. The simulation model was considered adequate because it accurately predicted high disease severity in susceptible cultivars without fungicide protection, and demonstrated a decrease in the disease progress curves with additional fungicide applications, similar to that observed in the plots. The model also generally predicted inadequate fungicide control, even with a 4-day spray interval, which also occurred in the field. Lack of adequate fungicide protection would indicate the need for cultivars with higher levels of durable resistance, and that farmers should consider more effective fungicides applications (higher dosages or different chemistries) if susceptible cultivars are used.

scholarly journals Control of speckled leaf blotch of wheat with fungicides

2000 ◽  
Vol 53 ◽  
pp. 103-108
Author(s):  
M.G. Cromey ◽  
M. Braithwaite ◽  
B.J.R. Alexander ◽  
S. Ganev ◽  
T.R. Cookson
Keyword(s):  
Disease Severity ◽  
Total Yield ◽  
Field Trials ◽  
Growth Stages ◽  
The South ◽  
Leaf Blotch ◽  
Fungicide Application ◽  
Low Levels ◽  
Disease Pressure

Two field trials were conducted in autumnsown wheat cv Domino which is highly susceptible to speckled leaf blotch in Central and South Canterbury Eighteen fungicide treatments were applied at two growth stages (tillering and ear emergence) at the manufacturers recommended rates Severity of speckled leaf blotch and other diseases was assessed on several occasions Speckled leaf blotch was severe in the South Canterbury trial but only low levels of the disease were recorded in the central Canterbury trial Most fungicides reduced disease severity and increased yield especially in the South Canterbury trial where disease pressure was highest and yield increases greater than 30 were recorded The second fungicide application appeared to provide most of the increase in yield The increases in thousand grain weights following fungicide applications contributed approximately onethird of the total yield increases in the South Canterbury trial and half in the Central Canterbury trial

Meta-Analytic and Economic Approaches for Evaluation of Pesticide Impact on Sclerotinia Stem Rot Control and Soybean Yield in the North Central United States

2019 ◽  
Vol 109 (7) ◽  
pp. 1157-1170 ◽  
Author(s):  
Jaime F. Willbur ◽  
Paul D. Mitchell ◽  
Mamadou L. Fall ◽  
Adam M. Byrne ◽  
Scott A. Chapman ◽  
...  
Keyword(s):  
Disease Severity ◽  
Yield Loss ◽  
Severity Index ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Soybean Yield ◽  
The North ◽  
Central United States ◽  
Meta Analyses ◽  
The Impact

As complete host resistance in soybean has not been achieved, Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum continues to be of major economic concern for farmers. Thus, chemical control remains a prevalent disease management strategy. Pesticide evaluations were conducted in Illinois, Iowa, Michigan, Minnesota, New Jersey, and Wisconsin from 2009 to 2016, for a total of 25 site-years (n = 2,057 plot-level data points). These studies were used in network meta-analyses to evaluate the impact of 10 popular pesticide active ingredients, and seven common application timings on SSR control and yield benefit, compared with not treating with a pesticide. Boscalid and picoxystrobin frequently offered the best reductions in disease severity and best yield benefit (P < 0.0001). Pesticide applications (one- or two-spray programs) made during the bloom period provided significant reductions in disease severity index (DIX) (P < 0.0001) and led to significant yield benefits (P = 0.0009). Data from these studies were also used in nonlinear regression analyses to determine the effect of DIX on soybean yield. A three-parameter logistic model was found to best describe soybean yield loss (pseudo-R2 = 0.309). In modern soybean cultivars, yield loss due to SSR does not occur until 20 to 25% DIX, and considerable yield loss (−697 kg ha−1 or −10 bu acre−1) is observed at 68% DIX. Further analyses identified several pesticides and programs that resulted in greater than 60% probability for return on investment under high disease levels.

Application of thiophanate-methyl at different host growth stages for management of sclerotinia stem rot in soybean

2004 ◽  
Vol 23 (10) ◽  
pp. 983-988 ◽  
Author(s):  
D.S. Mueller ◽  
C.A. Bradley ◽  
C.R. Grau ◽  
J.M. Gaska ◽  
J.E. Kurle ◽  
...  
Keyword(s):  
Stem Rot ◽  
Growth Stages ◽  
Sclerotinia Stem Rot ◽  
Thiophanate Methyl ◽  
Host Growth

Managing crop losses from foliar diseases with fungicides, rotation, and tillage in the Saskatchewan Parkland

2000 ◽  
Vol 80 (1) ◽  
pp. 169-175 ◽  
Author(s):  
K. L. Bailey ◽  
A. M. Johnston ◽  
H. R. Kutcher ◽  
B. D. Gossen ◽  
R. A. A. Morrall
Keyword(s):  
Disease Severity ◽  
Seed Weight ◽  
Crop Diversity ◽  
Stem Rot ◽  
Yield Response ◽  
Reduced Tillage ◽  
Leaf Spot Disease ◽  
Sclerotinia Stem Rot ◽  
Crop Losses ◽  
Foliar Disease

The effects of three tillage systems, three crop rotations, and fungicide applications were evaluated on diseases of barley, wheat, canola and pea at Melfort, SK, from 1994 to 1998. During these years, reduced tillage did not increase crop losses due to diseases. Four-year rotations with higher proportions of broad-leaved crops and more crop diversity (i.e., canola, pea, flax, and barley) had higher yields than rotations with fewer broad-leaved crops and less crop diversity (i.e., canola, wheat, barley, and barley). However, these rotations did not influence the severity of septoria leaf blotch of wheat, net blotch of barley, the incidence of sclerotinia stem rot and blackleg of canola, or the severity of mycosphaerella blight of pea. Interplot interference may have been a factor influencing some diseases in plots, as the size was only 270 m2. Fungicide application of propiconazole on Harrington barley decreased foliar disease severity and increased yield by 23%, seed weight by 13%, and kernel plumpness by 25%. Application of azoxystrobin decreased foliar disease and increased pea yield 29% and seed weight by 7% for the pea cultivars Express and Highlight. Foliar disease severity on AC Taber wheat was reduced by application of propiconazole in 2 of 4 yr, but the yield response was very inconsistent. Similarly, AC Excel canola had inconsistent disease and yield response to applications of propiconazole and benomyl, but levels of sclerotinia stem rot and blackleg were very low in all years. These results indicate that reduced tillage will not result in significantly higher levels of disease that require fungicide inputs to maintain yield. Moving from cereal-based rotations to more diverse, broad-leaved based rotations improves the yield of cereals. However, regardless of tillage or rotation, higher yields may be obtained in barley and pea with fungicides for control of leaf spot disease in susceptible cultivars. Key words: Plant disease, rotation, tillage, fungicides, yield loss

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